Abrasive and process of making the same



UNITED STATES WILLIAM STRUTT, F PITTSBURGH, PENNSYLVANIA, ASSIGNOR 'IO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ABRASIVE AND PROCESS OF MAKING THE SAME.

No Drawing.

' To all whom it may concern:

a new and useful Improvement in Abrasives and Processes of Making the Same, of which the following is a. specification.

My invention relates to the manufacture of abrasive bodies, and it has for one of its objects to provide a simple, inexpensive and effective process of treating abrasive materials for the purpose of greatly increasing their effective life and efliciency.

Another object of my invention is to provide a new and superior abrasive article having superior grinding properties and having, in particular, the property of being self-cleaning, that is to say, of repelling from its surface the particles ground off from the materials to which the abrasive may beapplied.

Certain very hard abrasive materials, such as carborundum and corundum, are well adapted for use in the grinding and polishing of metals, and for this purpose they are commonly formed into rectangular blocks of sizes convenient for handling. It is found that, when such abrasive blocks are used to grind relatively soft and malleable materials, such ascopper, some of the particles ground off by the abrasive block are retained upon its surface, entering between the fine tooth-like cutting projections of the abrasive, and destroying its cutting power to a considerable extent. When such a block is used thereafter, its effect upon the material being ground is to rub off the surface of the material instead of cutting or grinding it.

I have discovered that the foregoing disadvantage may be overcome bf; impregnating the abrasive bodies with certain oils, which appear to cause the surfaces of the cutting teeth of the abrasive to repel the fine particles of copper or other such material, and which thereby render the cutting surfaces of the abrasive self-cleanin The abrasives consequently have a muc longer effective life and an increased degree of efficiency.

In carrying out one modification of my Specification of Letters Patent.

Patented Dec. 9, 19119.

Application filed March 4, 1915. Serial No. 12,206.

process, I make use of carborundum grinding stones of any ordinary sizes, such as 1 by 2 by 8 inches, and I immerse the stones in a relatively light hydrocarbon machine oil for a considerable time, until the blocks have absorbed as much of the oil as possible. I have found that this maximum absorption takes place in somewhat less than one hundred hours, and I therefore prefer toallo-w the blocks to soak in the machine oil for about one hundred hours, after which I remove them from the oil and ignite the oil which drips from the surfaces of the blocks. to burn until oil ceases to drip from the blocks, at which time the flame should be extinguished, and the blocks allowed to cool. They are then ready for use. 7

I have found that carborundum blocks absorb at least 8% of their weight of light hydrocarbon machine oil, and I have also found that the burning treatment, described above, greatly improves the cutting properties of the blocks, although the exact reason for this improvement is not clear.

Abrasive blocks prepared in accordance with my invention may be used for grinding soft metals, such as copper, at very high speeds, which has heretofore not been possible with the abrasives commonly used, on account of the surface accummulations of ground material mentioned above. This property of my improved abrasive materials renders them particularly well adapted for use in grinding the commutators of dynamo-electric machines, which must be ground while rotating at high peripheral speeds.

The steps of my process and the materials employed may be variously modified without departing from the principles of my invention, and it is therefore to be under stood that my invention is not restricted to the precise process steps and substances mentioned above, scope of the appended claims.

I claim as my invention:

1. A process of treating bodies of abrasive material that comprises impregnating the bodies with an oil and then burning the adhering oil from the surfaces of the blocks.

2. A process of improvin the abrasive properties of carborundum b ocks that combut is limited only by the The surface oil should be allowed prises immersing the blocks in a nhi-neral oil In testimony whereof, I have hereunto' until the blocks have absorbed a substantial subscribed my name this 26th day of Feb, quantity of the oil, removing the blocks 1915.

from the oil, igniting the oil -zwlhering to WM. STRUTT. 5 the surfaces .of the blocks, and extinguishing Witnesses:

glue 1gimme when oil ceasesto drip from the PARKER N FF, 

